Show different classification classes as different colors on a timeseries plot

Question

I want to visualize a line plot of time series with different classes in the background in python.

Suppose if I have time series of 5 minutes with 3 classes as shown in the table 1.

Time start	Time End	Class
00:00:00	00:00:30	1
00:00:31	00:01:30	2
00:01:31	00:04:00	3
00:04:01	00:05:00	2

I also have pressure values every 10 seconds shown in table 2.

Time End	Pressure
00:00:10	0.2
00:00:20	0.3
00:00:30	0.53
.	.
.	.
00:04:50	0.7
00:05:00	0.92

I want to plot a line graph on top of the classes with different colors as shown in the figure below. The line plot follows the table 2 and the background color of the line plot follows table 1.

I am open to use any python library that could help me complete this visualization.

Answer 1

You can use the following snippet:

# convert timestamp to seconds
df2['Time End'] = pd.to_timedelta(df2['Time End']).dt.total_seconds()
df1['Time start'] = pd.to_timedelta(df1['Time start']).dt.total_seconds()
df1['Time End'] = pd.to_timedelta(df1['Time End']).dt.total_seconds()

# plot line
ax = df2.plot(x='Time End', y='Pressure')
ax.set_ylabel('Pressure')

# plot spans
colors = {1: '#D9E8FB', 2: '#F7CECC', 3: '#FFF2CD'}
for _, (x1, x2, c) in df1.iterrows():
    ax.axvspan(x1, x2, color=colors[c])